Leaf Spring opinions

[ScrapIron]

I am working on the rear suspension on my 2005 Chinook again after being bad sick since last september, not covid related. I ordered the Sky Offroad shackle flip kit which arrived today but now i need some leaf springs.

I already finished the front end using a Dana 60 out of a 2005 F-350 Super duty 4x4. Everything on the front is brand new and ready to go. Now i need some nice leaf springs for the back to raise it. Currently it has air suspension on it which i will remove and replace with leaf springs.

I got a quote from Alcan springs of $1700 for the springs with a 6 to 7 week production time. Does anyone have opinions on the quality of their product or should i look at Deaver springs or atlas etc....?

My next thought is.... should i even use the shackle flip kit or should i just try to gain all the height i need with the springs, or considering the weight of this truck, would i be better off utilizing the shackle flip kit in combination with a spring with less arch in order to avoid potential spring sag?

Originally this truck came with springs from ford with very little arch to them at all. Ford part number 5C2Z-5560-VA. The truck is quite heavy at 11640 pounds with 7840 pounds of that being on the drive axle.

By the way, i ordered the Sky shackle flip RAW steel. The reason is because everytime i order and pay extra for powder coating its never done correctly and the powder coat starts to crack and fall off in short order and then of course the parts begin to rust. I decided powder coating is a waste of money and i would do better to prep the parts and spray them with paint myself.

[carringb]

I would use either the shackle kit with stock springs (maybe add a leaf at most), or taller springs without the shackle kit. If you try to combine both, the driveline angle will be way off. Even with the stock springs the shackle kit might put the angle off just enough to cause vibration. If that's the case, the fix is super easy... just add some caster alignment shims from an F650 front axle.

What kind of air system do you have now? And why do you want to remove it?

[ScrapIron]

Originally Posted by carringb

I would use either the shackle kit with stock springs (maybe add a leaf at most), or taller springs without the shackle kit. If you try to combine both, the driveline angle will be way off. Even with the stock springs the shackle kit might put the angle off just enough to cause vibration. If that's the case, the fix is super easy... just add some caster alignment shims from an F650 front axle.

What kind of air system do you have now? And why do you want to remove it?

Its not a matter of wanting to scrap the air system. Its more a matter of i installed a dana 60 under the front of the truck and it has raised the truck beyond what the air system can compensate or be adjusted for. I could remanufacture all of the brackets and make it work, i just dont want to.

Its the Reyco/Granning RD800F system.

https://reycogranning.com/suspensions/model-rd800f/

[ScrapIron]

Here is the system on my truck. Note that it utilizes an S spring in unison with an air spring. Not unlike the shackle flip kit, when you over extend the air bags it cause the S spring to rotate at it mount point on the forward frame rail effectively changing pinion angle as well as moving the axle forward slightly.

I could keep it like i stated and rebuild all of the brackets including the front frame rail brackets. I just dont want to, i want to switch to leaf springs so i have little to no maintenance or worry about rear suspension components. Im sure running just leaf springs will degrade my ride quality, but thats a sacrafice i am willing to make. Air suspension is not a maintenance free system.

Im lost on the F650 caster shims youre mentioning. Are they for the rear axle?
My front suspension utilizes 4 link radius arms and they are adjustable so adjusting caster on the front of the truck is a breeze.

[ScrapIron]

Is this image what youre referencing? Item number #5336?

[carringb]

Correct. The F650 alignment shims (5336) are likely needed on the back axle, if you use the shackle flip kit, in order to maintain an in-spec pinion angle.

[Lilnuts2]

Scrapiron, the first thing I would do go to a scale with your rig loaded how you use it. Get a separate front and rear axle weight. Park on level ground and measure your existing pinion angle. Then measure the elevations of your spring mounting points and your axle spring pad. Determine how much lift you want. With that info any spring shop can build you exactly the springs you want. Don't get caught up with all the name brand spring shops there are a lot of good ones you don't hear about.
If you do need to adjust your pinion angle you can buy tapered shims with any degree you need to get the corrected angle.
Like what carringb mentioned.

[motovan_mn]

Originally Posted by ScrapIron

I got a quote from Alcan springs of $1700 for the springs with a 6 to 7 week production time. Does anyone have opinions on the quality of their product or should i look at Deaver springs or atlas etc....?

For what it's worth, Ujoint Offroad switched to using Alcan springs for all of their mail-order shipments. They still use Atlas for their in-house builds. I think it was mostly a matter Atlas not being able to keep up with their demand, but it shows that Chris thinks highly of Alcan!

I believe Justin at UJOR CO is also running Alcan springs on his personal van, though I'm not positive.

[ScrapIron]

Just tried mowing the lawn and now im sick after 15 minutes. Not sure im going to be able to finish this project.

[carringb]

Another idea…. What about adding a 2” lift block under the Reyco-Granning leaf, and swapping in 2” taller airbags?

Seems like you have such a nice suspension now, you’d be going backwards going to leafs.